The present invention relates to a method and apparatus for heating a zone of an elongate tubular article, for example a zone of the surface of a pipeline in the course of applying a sleeve or patch on coated pipes, employing a hot gas source, such as a heater device that provides a heated air stream, or when using a flame, such as a torch flame to heat the pipe.
Heating may, for example, be employed for heating a pipeline weld joint and the adjacent coating in the field to a temperature suitable for subsequent installation of a covering. In particular, the present method and apparatus are especially useful where the temperature to which the line coating must be heated exceeds its melting point, and the covering is to be applied is a heat shrinkable sleeve, tape or patch coated with a hot melt adhesive whose adhesive requires the substrate to be heated to a temperature close to or above the melting point of the substrate. More particularly, the method is especially advantageous when the coating on the pipeline is polypropylene, and the hot melt adhesive on the sleeve, tape or patch requires the substrate to be at least 160° C. in order to achieve an acceptable bond.